US regulators have cleared Tesla after an investigation proved no evidence of fault or defect in the Tesla S electronic systems. The investigation centered on the death of a man whose Model S collided with a crane while he was using the car’s autopilot system.

After a six-month investigation, a report said the US National Highway Traffic Safety Administration (NHTSA) would not seek a vehicle recall. Tesla confirmed that the safety of its customers comes first. It said it appreciated the report and its findings.

Joshua Brown, 40, was killed in a collision while using Tesla’s autopilot system in his Model S in Florida last May. Tesla has since improved the system and added new restrictions on hands-free driving.

The investigation was closely monitored by other carmakers who are introducing drivers’ assistance and semi-autonomous features in their products. The updated Tesla system warns drivers to take back control periodically and not rely totally on autonomous driving.